Subcycle spectral structures and dynamics of high-order harmonic generation(HHG)processes of atoms and molecules driven by intense laser fields on the attosecond time scale have been originally studied theoretically a...Subcycle spectral structures and dynamics of high-order harmonic generation(HHG)processes of atoms and molecules driven by intense laser fields on the attosecond time scale have been originally studied theoretically and ex-perimentally.However,the time scale of HHG dynamics in crystals is in the order of sub-femtosecond,and the carrier dynamics of HHG in crystals driven by subcycle laser pulses are largely unexplored.Here we perform a theoretical study of subcycle structures,spectra,and dynamics of HHG of crystals in mid-infrared laser fields subject to excitation by a subcycle laser pulse with a time delay.The HHG spectra as a function of time delay between two laser fields are cal-culated by using a single-band model for the intra-band carrier dynamics in crystal momentum space and by solving the time-dependent Schr?dinger equation in velocity gauge for the treatment of multi-band crystal systems.The results exhibit a complex time-delay-dependent oscillatory pattern,and the enhancement and suppression of the HHG related to subcycle pulse are observed at the given time delay in either single-band or multi-band crystal systems.To understand oscillation structures with respect to the dependence for the subcycle laser fields,the time-frequency characteristics of the HHG as well as the probability density distribution of the radiation are analyzed in detail.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074239 and 91850209)the Natural Science Foundation of Guangdong Province,China(Grant Nos.2020A1515010927 and 2020ST084)+3 种基金Department of Education of Guangdong Province,China(Grant Nos.2019KTSCX038 and 2020KCXTD012)Shantou University(Grant No.NTF18030)the Natural Science basic Research Program of Shaanxi Province,China(Grant No.2022JM-015)Scientific Research Foundation of SUST(Grant No.2017BJ-30).
文摘Subcycle spectral structures and dynamics of high-order harmonic generation(HHG)processes of atoms and molecules driven by intense laser fields on the attosecond time scale have been originally studied theoretically and ex-perimentally.However,the time scale of HHG dynamics in crystals is in the order of sub-femtosecond,and the carrier dynamics of HHG in crystals driven by subcycle laser pulses are largely unexplored.Here we perform a theoretical study of subcycle structures,spectra,and dynamics of HHG of crystals in mid-infrared laser fields subject to excitation by a subcycle laser pulse with a time delay.The HHG spectra as a function of time delay between two laser fields are cal-culated by using a single-band model for the intra-band carrier dynamics in crystal momentum space and by solving the time-dependent Schr?dinger equation in velocity gauge for the treatment of multi-band crystal systems.The results exhibit a complex time-delay-dependent oscillatory pattern,and the enhancement and suppression of the HHG related to subcycle pulse are observed at the given time delay in either single-band or multi-band crystal systems.To understand oscillation structures with respect to the dependence for the subcycle laser fields,the time-frequency characteristics of the HHG as well as the probability density distribution of the radiation are analyzed in detail.
